They are together nearly every other weekend, plus school vacations and holidays. Together they fish, ski, and jog - actually Perry often paces his dad, who works at WGBH-TV, by riding his bike. Indoors, they play chess, race slot cars, and build model railroads.

The railroad layout is now in Perry's bedroom, and a recently acquired, four-lane slot-car race track fills one side of the living room.

Marotta admits there's a Toys-R-Us quality to his apartment, but says a boy-friendly atmosphere is "important to make sure Perry doesn't simply have a bed in the corner. His home is as much here as it is in New Jersey. When he's here, he has a number of options."

Marotta wanted plenty of space and found prices much more affordable in Lowell, Mass., than 30 miles away in Boston, where he works. He loves the 14-foot ceilings, the health club, and swimming pool privileges, and the better proximity to New England ski country since father and son frequently hit the slopes.

Model railroading was one of Marotta's boyhood hobbies, and when Perry was still a toddler Marotta dug the set out. "The exposure was there from seeing his dad build this empire," Marotta says of Perry's interest in the pastime. The two have worked on building a tunnel and mountainous scenery together.

Marotta says he doesn't study the art of fathering. But he does bone up on the mechanics of model railroading or slot cars. That, he says, helps pave the way to a happy, productive, shared experience. "I don't want to ...say, 'I don't know how this works,' and put it away," he says. "I never, ever want that to happen."

As for fishing, Marotta says, experience has taught him not to try to fish at the same time as his son. "It doesn't work. Until he learns the technique, you you have to focus on him. Otherwise he's not going to have fun and you're not going to have fun."

When a child shuttles between divorced parents, Marotta says, the child may feel a heightened need for connecting - whether through hobbies or over dinner. "You are always without the other parent," he explains.

To bridge the gap when Perry is at his New Jersey home, Marotta calls daily. "Between 7 and 8 that call's going through," he says. "Perry may not be interested in talking. That's OK, as long as he's got the reminder that dad still cares, that he's still connected to dad."